Apparatus for the controlled heating of fabrics with an air/steam heating medium



July 2 1955 H D. TERHUNE ETAL 42 APPARATUS FOR THE CONTROLLED HEATING OFFABRICS WITH AN AIR/STEAM HEATING MEDIUM Filed Dec. 51, 1962 M R OMEN MOU OMH M R M E LF DD WH MR6 AAU JHH BY v b AGENT United States Patent3,196,642 APlARATUS FOR THE CONTROLLED HEATING 0F FABRIQS WITH ANAnt/STEAM HEATING MEDIUM Hugh 1). Terhune, Wilmington, and Harold F.Porter, Hoclressin, lDeL, and James L. Moore, Charlotte, N.C., assignorsto E. I. du Pont de Nemours and Company, Wilmington, DcL, a corporationof Delaware Fiied Dec. 31, 1962, Ser. No. 248,332 6 Claims. (Cl. 68-5)This invention relates to apparatus for heating textile fabrics and fortemporarily storing the heated fabric therein.

Textile fabrics, in open-width or rope form, are subjected in variouscommercial scouring, bleaching and similar operations to the action of.a hot fluid such as steam for the purpose of heating the fabric toaccelerate or improve the action of a treating agent on the fabric.Continuous operations of this type usually involve the steps ofimpregnating or dampening the fabric with a treating liquor such as ableach or scouring solution, heating the impregnated fabric with livesteam and storing the heated fabric temporarily in a device such as aJ-box, all such steps being carried out continuously on a continuouslyadvancing strand of the fabric. J-box systems for carrying out suchoperations are described in Campbell et al. US. Patent 2,267,718 andBell et al. US. Patent 2,858,184. Such J-box systems are generallyregarded as closed systems in that they are essentially closed to thesurrounding atmosphere except only for ports or openings for the entryand exit of the strand of fabric.

Closed I-box systems of the type described in the above patents arewidely used and give excellent results employing live steam as theheating fluid to achieve and maintain fabric treating temperaturesapproaching the atmospheric boiling point of water. However, in certainoperations such as the bleaching of colored yarn and certain types ofcotton-synthetic fabrics, such high temperatures cannot be tolerated andfabric temperatures ranging from about 200 F. down to as low as 150 F.are often required. Uniform fabric heating to such lower temperatures isdificult to achieve and maintain in J-box systems of the above type.

Poesl US. Patent 2,346,186 proposes a modification of the J-box systemof Patent 2,267,718, which modification involves a separate relativelylong U-shaped heater tube through which the fabric is passed prior toits entry into the ]-box. Heating is effected by passing steam throughthe tube in a direction counter to the direction of travel of thefabric. It is disclosed that the temperature of the steam employed canbe lowered from 212 F. to 200 F. or lower by mixing suitable amounts ofair with the steam. The patent shows a device employing a steam jet toaspirate air into the steam used.

Poesls modified .l-box system functions fairly well to produce fabrictemperatures down to about 205 F. However, for achieving substantiallylower fabric temperatures the system is both inefficient and difficultto control. In such a system, the amount of steam required to aspiratesutficient air to produce desired relatively low fabric temperatures isoften far in excess of the amount of steam;

,. ICC

delivered to the heater tube is too small to maintain the slightpositive pressure in the I-box that is necessary to prevent entrance ofexcessive amounts of air into the system, e.g. at the fabric entranceand exit ports.

It is an object of the invention to provide an improved apparatus forcontinuously heating an advancing strand of fabric and temporarilystoring the heated fabric. A further object is to provide an improvedclosed J-box system of the above type wherein controlled fabrictemperatures over a wide range below the atmospheric boiling point ofwater can be readily and eiliciently obtained. A still further object isto provide a J-box system employing steam/ air mixtures as the fabricheating media, which system permits highly effective control of thetemperature to which the fabric is heated over a range of from about F.to 205 F. Other objects will be apparent from the following description.

The objects of the invention are accomplished by a J- box system inwhich a substantially constant volume of air is continuouslyrecirculated through that portion of the system wherein heating of thefabric is effected while steam is fed into the recirculating air streamin controlled amounts as required to produce the air/steam mixturenecessary for a given desired fabric temperature. The accompanyingdrawing is a perspective view of a .T-boX system designed in accordancewith the invention.

In the drawing, reference numeral 1 refers to a closed J-box of thegeneral type described in Bell et a1. Patent 2,858,184. J-box 1,comprises a long vertical leg 2, a short vertical leg 3 with fabric exitport 5, an intermediate curved section 4, a hood section 6 and a fabricentrance leg 7 with fabric entrance port 8. Heating of the fabric iseffected in hood 6 and fabric entrance leg 7, which together constitutethe heating zone wherein the fabric strand 9 is contacted directly withthe gaseous heating medium. Leg 2, section 4 and leg 3 of the J-boxconstitute the storage zone thereof wherein the heated fabric is storedtemporarily to complete the action of the treating agent upon thefabric.

In hood 6 is positioned a fabric forwarding mechanism or means forcontinuously advancing the fabric, such as draw reel 11, indicated inthe cut-away portion of the drawing, and means (not shown) for plaitingfabric strand 9 as it drops down from draw reel 11 into a compact fabricpile or mass 10 in leg 2. A suitable mechanism for use in conjunctionwith draw reel 11 whereby an advancing strand of fabric in ropeform ispiled in a compact plaited form uniformly across the cross-section ofleg 2 is shown in detail in Patent 2,858,184. Other piling and plaitingmechanism, many of which are well known, may also be employed. Thus,Terhune US. Patent 2,939,- 306 shows a plaiting mechanism for use inconjunction with a draw reel such as draw reel 11 when the .l-box isintended to handle cloth strand in open width form.

In operation, the continuous fabric strand 9 is drawn through entranceport 8 by draw reel 11. Heatiug of strand 9 is effected by its directcontact with the gaseous heating medium in leg 7 and hood 6. As strand 9drops down from draw reel 11, it is pla-ited in leg 2 by the action ofany suitable plaiting mechanism so as to form a compact fabric pile 1%from which strand 9 is pulled, by means not shown, through exit port 5.

An air/steam mixture of a composition that will produce the desiredfabric temperature is passed into hood 6 by way of heating mixtureentrance pipe 12 and distributor box 13, the latter being designed so asto distribute the heating mixture evenly across the Width of hood 6. Theheating mixture flows through hood 6 and down fabric entrance leg 7counter to the direction of travel of strand 9'therein. Much of thesteam supplied in the heating mixture will be condensed upon the fabricas the latter is heated. A spent mixture of the air component n r d3 ofthe original heating mixture and residual steam that is not so condensedis exhausted from the lower portion of fabric entrance leg 7 andreturned to blower 22 by way of return pipes 14, 16, and 19. Return pipe15, which connects with return pipe 16, provides for the return toblower 22 of any heating mixture that may have leaked past fabric pileit) into the upper part of leg 3 of the J-box. When an efficientplaiting mechanism is employed for piling fabric strand 9 in leg 2, suchleakage of the heating mixture will be slight due to the sealing actionof fabric pile lit; hence, return pipe 15 is not to be regarded asessential to the J-box system of the invention. However, return toblower '22 of any portion of the heating mixture which would otherwisebe exhausted to the atmosphere and lost improves heating efiicien cy andis generally Worthwhile.

Return pipes 14, 15, i6 and 19 together with heating mixture entrancepipe 12, constitute conduit means which, along with hood 6 and fabricentrance leg '7 constitute a cyclic path through which the air componentof the heating mixture is continuously recycled by means of blower 22.Feeding into return pipe 19 of that cycle are steam supply pipe 1-7 andair supply pipe 20, the latter being provided with valve 27 and filter21. Temperature sensing element 23 in pipe 12 is connected with atemperature recorder and control mechanism 24 which actua-tcs steam flowcontrol valve 18 in pipe 17 so as to increase or decrease the flow ofsteam from pipe 17 into the cycle as required to maintain thetemperature of the heating mixture at a desired constant value as itflows from pipe 12 into hood 6. Temperature sensing element 25 in curvedsection 4 of the l-box and temperature indicator or recorder 26connected therewith provide a continuous indication of the temperatureto which the fabric is being heated. If a higher or lower fabrictemperature, as indicated by recorder 26, is required or desired,control mechanism 2d is adjusted so as to cause steam control valve 18to adjust the steam supplied to the cycle in accordance with the fabrictemperature desired.

The J-box system illustrated in the drawing is essentially orsubstantially a closed system since the only significant openingstherefrom to the surrounding atmospher are fabric entry and exit ports 8and 5, respectively. During continuous operation to heat the fabric to agiven temperature,gas flow through ports 8 and is generallyinsignificant. However when control mechanism 24. is adjusted to changethe operation from a higher to a lower temperature, less steam will beadmitted via pipe 117 and air as required toprovide the new air/ steamcomposition corresponding to the desired lower t mperature will be drawnin via ports 8 and 5. On the other hand, when control mechanism 24 isadjusted to change the operation from a lower to a higher temperature,more steam will be admitted via pipe 17 and spent heating mixture willbe vented to the atmospherevia ports 8 and '5 as required to provide thenew air/steam composition correspondingto the desired highertemperature. Such entry of air into .orventing of spent heating mixturefrom the system via ports 8 and 5 will occur to any significant extentonly-during the short periods of adjustment from one operatingtemperature to another. Air required for changing from a higher to alower temperature can also be admitted via line Zil by opening valve 27.Any air admitted via line 20, which is preferably first passed throughfilter 2-1 to remove dust particles, can be supplied from thesurrounding atmosphere or from a high pressure air system, not shown inthe drawing.

The novel arrangement for supplying to the heating zone of the J-box andair/steam mixture of the composition required to produce the intendedfabric temperature makes possible use of the J-box system to obtain anydesired'fabric temperature over a wide range of temperatures. The systemis flexible and can be adjusted at will to change the temperature towhich the fabric will be heated. Moreover, fabric temperature is readilyand effectively con- I trolled at the desired value under highlyefiicient heating conditions. Since essentially no hot gases areexhausted to the atmosphere under fixed operating conditions, Wastefulheat losses are low and the rate of flow of the heating mixture incontact with the fabric strand in the J-box can be greatly increased,e.-g. to values that would beeconomically impractical where the spentheating mixture is simply exhausted to the atmosphere as in prior J-boxsystems. Such increased rates of flow of the heating mixture increasesthe rate of heat exchange to the fabric and faciliates uniform heatingof the fabric.

It will be apparent from the foregoing description that the fabricheating and storage system of the invention comprises the combination ofa closed fabric heating and storage apparatus such as a closed J-boxwith a piping assembly that establishes a confined cyclic flow path foran air/ steam heating medium, which path includes as an integral partthereof the heating zone of the J box wherein a continuously advancingstrand of the fabric is heated by direct'oontact with the .air/ steamheating medium. The cyclic flow path is provided with means such as ablower for maintaining a continuous rapid How of the heating mediumtherein whereby the spent heating medium withdrawn from the heating zoneof the J-box is continuously recycled to said heating zone, and alsowith means for injecting steam and air (when required) into the recyclestream of the heating medium in'such amounts as are required to maintainthe heating medium entering the heating Zone of the J-box at a desiredconstant composition.

It will be obvious that various modifications and adaptations of thepreferred embodiment of the invention illustrated by the drawing may bemade without departing from the scope and spirit of the invention. Thus,entrance leg 7 of the I-box shown in the drawing, which in reality isbut an extension of the hood portion of the ]-box, may be arrangedhorizontally or in any other desired position, orit may be dispensedwith enti ely if desired but at a sacrifice in heating efficiency. Aseparate heating tube such as that described in Poesl Patent 2,346,186may be employed whether in addition to or in place of fabric entranceleg '7, provided such separate heating tube is included as an integralpart of the cyclic flow path for the air/steam heating medium. Draw reel11 of the drawing may be replaced by a plurality of draw reels or by anyother suitable mechanism for continuously drawing the fabric strand intohood 6. As indicated previously, any suitable plaiting or piling means Y'may be employed for piling the heated strand evenly across thecross-section of the storage portion of the Lbox. Furthermore, thedirection of flow of the air/ steam heating medium through the hood ofthe J-box may be reversed so that the heating medium and the fabric willtravel in the same direction. In such modification, which is distinctlynot preferred, the recycled and reconstituted air/steam heating mediumwould enter the lower portion of fabric entrance leg '7 while the spentheating medium would be withdrawn from hood 6 of the J-box.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined a follows:

ll. Apparatus for continuously heating textile fabric preimpregnatedwith a treating liquid and for temporarily storing the heated fabrictherein, said apparatus comprising a substantially closed I-box andmeans to continuously advance a strand of fabric therethrough, saidJ-box including a fabric heating zone having a fabric entrance port anda fabric storage zone having a fabric exit port, means to supply an'air/steam heating medium directly to said heating zone and the fabricadvancing therethrough, said fabric storage zone being utilized totemporarily store said heated fabric in a compact mass, conduit meansand circulating means for said heating medium, said conduit meansextending from said circulating means to said heating zone and from saidheating zone to said circulating means, and means for continuouslysupplying a controlled amount of steam to said heating medium in saidconduit means.

2. Apparatus for continuously heating textile fabric preimpregnated witha treating liquid and for temporarily storing the heated fabric therein,said apparatus comprising a substantially closed I-box and means tocontinuously advance a strand of fabric therethrough, said J-boxincluding a fabric heating zone having a fabric entrance port and afabric storage zone having a fabric exit port, means to supply an air/steam heating medium directly to said heating zone and the fabricadvancing therethrough, said fabric storage zone being utilized totemporarily store said heated fabric in a compact mass, conduit meansand circulating means for said heating medium, said conduit meansextending from said circulating means to said heating zone and from bothsaid heating zone and said storage zone to said circulating means, andmeans for continuously supplying a controlled amount of steam to saidheating medium in said conduit means.

3. Apparatus for continuously heating textile fabric preimpregnated witha treating liquid and for temporarily storing the heated fabric therein,said apparatus comprising a substantially closed J-box and means tocontinuously advance a strand of fabric therethrough, said J-boxincluding a fabric heating zone having a fabric entrance zone and afabric storage zone having a fabric exit port, means to supply an air/steam heating medium directly to said heating zone and the fabricadvancing therethrough, said fabric storage zone being utilized totemporarily store said heated fabric in a compact mass,

conduit means and circulating means for said heating medium, saidconduit means extending from said circulating means to said heating zoneand from said fabric entrance zone to said circulating means, and meansfor continuously supplying a controlled amount of steam to said heatingmedium in said conduit means.

4. Apparatus according to claim 1 wherein the circulating means is ablower.

5. Apparatus according to claim 1 wherein the means to supply thecontrolled amount of steam includes a valve actuated by a temperaturesensing means positioned in the conduit means extending from thecirculating means to the heating zone.

6. Apparatus according to claim 1 Which includes means for supplying airto said heating medium in said conduit means.

References Cited by the Examiner UNITED STATES PATENTS 955,001 4/10Schilde 68--6 2,157,975 5/39 Wilson 685.3 2,008,230 7/35 Spooner 68-5.42,346,186 4/44 Poesl 68-6 2,858,184 10/58 Bell 68-178 X 3,027,740 4/62Sonnino 68-5.5 3,067,602 12/62 Brunt 685.5

IRVING BUNEVICH, Primary Examiner.

WALTER A. SCHEEL, Examiner.

1. APPARATUS FOR CONTINUOUSLY HEATING TEXTILE FABRIC PREIMPREGNATED WITHA TREATING LIQUID AND FOR TEMPORARILY STORING THE HEATED FABRIC THEREIN,SAID APPARATUS COMPRISING A SUBSTANTIALLY CLOSED J-BOX AND MEANS TOCONTINUOUSLY ADVANCE A STRAND OF FABRIC THERETHROUGH, SAID J-BOXINCLUDING A FABRIC HEATING ZONE HAVING A FABRIC ENTRANCE PORT AND AFABRIC STORAGE ZONE HAVING A FABRIC EXIT PORT, MEANS TO SUPPLY ANAIR-STEAM HEATING MEDIUM DIRECTLY TO SAID HEATING ZONE AND THE FABRICADVANCING THERETHROUGH, SAID FABRIC STORAGE ZONE BEING UTILIZED TOTEMPORARILY STORE SAID HEATED FABRIC IN A COMPACT MASS, CONDUIT MEANSAND CIRCULATING MEANS FOR SAID HEATING MEDIUM, SAID CONDUIT MEANSEXTENDING FROM SAID CIRCULATING MEANS TO SAID HEATING ZONE AND FROM SAIDHEATING